Custom business logic is a term that we define in our proposals with the following text:

"Not all web pages are created equal. Some pages simply display content like text, pictures, captions, and links. Other pages need to "make decisions" about what information to display and how to display it. For example, a product page might simply display the content associated to a particular product, this would not require any custom business logic. However, a similar page might need to "decide" what price to display based on the user, or provide links to PDF tech sheets only if there are any associated to that product. When pages need to "make decisions" we need to program in custom business logic. We estimate custom business logic on case-by-case basis."

Depending on the particular needs of a website, custom business logic can add a tremendous amount of complexity and cost to a web project. For instance, consider a typical website page that contains some text, an image, and a few documents. A standard page will display the same content to anyone that visits the page. Now contrast that to the typical extranet or intranet page where, depending on what user is accessing the page and their level of authorization, the page will display completely different (personalized) content. If a sales representative visits the page, they might see vastly different information than a CEO visiting the exact same page. Custom business logic is required in these instances to enable a web page to "make decisions" about what information to display to a particular user. The needs and uses for custom business logic are limitless. When multiplied out over an entire site, custom business logic can easily turn a very small site into a very large project. For this reason, a raw site page count will typically have less impact on a project budget than the complexity of the site's pages. We have built some very large sites for relatively small budgets, because their pages were all relatively simple in their structure. By contrast, we have built some relatively small sites that have required large budgets to account for the complexity of all the relationships between content and users on the site. The degree of custom business logic is always an individual line item that affects the final cost.